Note that the laws of thermodynamics only specify the minimum number of calories you must consume (i.e., to not lose weight, or to not die).
There is no real maximum to the amount of calories your body can waste (as heat or by excretion). Nor is there any law saying that we're all equally efficient (or even close).
There is no real maximum to the amount of calories your body can waste (as heat or by excretion). Nor is there any law saying that we're all equally efficient (or even close).